1. Field of the Invention
The present invention relates to a method of manufacturing an optical waveguide device by use of photo-curable resin solutions and light. Particularly, it relates to a method of manufacturing a firm optical waveguide device having an optical waveguide retained by a retention member including an optical component. This invention is applicable to an optical waveguide device inexpensive in cost and low in loss in optical fiber communication, such as an optical transmitter/receiver, an optical interconnection, an optical demultiplexer or an optical multiplexer.
2. Description of the Related Art
A technique using a photo-curable resin solution for forming an optical waveguide at a forward end of an optical fiber has been noticed in recent years. For example, Unexamined Japanese Patent Publication No. Hei. 4-165311 has disclosed a method of manufacturing an optical waveguide. To give a brief description, the method has a first step of immersing an end of an optical fiber in a photo-curable resin solution, for example, made of a fluorine-based monomer, and a second step of emitting light of a wavelength from the forward end of the optical fiber to thereby cure the solution with the light.
For example, when laser light of a wavelength near an ultraviolet range or of a short wavelength is emitted from the end portion of the optical fiber, the photo-curable resin solution at the forward end portion of the optical fiber is cured by photopolymerization reaction. From the emitting end, there is formed a so-called core portion based on the power distribution of the light. When the core portion is formed, the light is propagated further forward and forms another core portion continuously and successively. As a result, an optical waveguide is formed.
The method has a third step of extracting the thus formed optical waveguide from the photo-curable resin solution and removing the remaining photo-curable resin solution by cleaning or the like. The method further has a fourth step of coating the optical waveguide with a light-transmissive resin. This step is performed for covering the core surface and protecting the core surface from being contaminated with dust or from being damaged.
In the related-art example, however, the end surface of the optical waveguide formed thus was not an optical surface. For this reason, it was necessary to provide a fifth step as the final step of cutting and polishing the forward end surface of the thus formed core portion to thereby form an emitting surface of the optical waveguide. Further, in the related-art example, the formed core portion ceased at a transmission line length of 8.5 mm. When surface treatment was subjected to the end surface of the core portion, the transmission line length was further reduced. Although this reduced transmission line length was applicable to a connector for connecting optical fibers to each other, this length was difficult to form an optical waveguide device such as a demultiplexer/multiplexer having a branching mirror inserted in the middle of the transmission line.
Further, in the third step, when the formed optical waveguide was extracted from the photo-curable resin solution, the optical waveguide was bent, so that there arose a problem in coupling the optical waveguide with another optical component.